Password systems have been used with computer based machines for many years. A typical password may be, for example, a four-digit number, for example ‘1234’. In such a case if one wants to start using a particular computer program or for the computer based machine to perform a certain action, the machine asks a password, and if in this case, the number ‘1234’ is entered (usually via a keyboard or keypad, but equivalent ways may be via speaking a word into a language recognition system, etc), then the particular computer program or action starts. If the wrong password, for example in this case, ‘1234’, was entered, then the particular program or particular action would not occur, and the user may (or may not) receive an error message from the computer.
Many password systems exist. While a four-digit number is a popular system, used at automatic bank machines, for example, many other password systems use longer numbers or also allow a wider variety of alphanumeric characters. More possibilities in a password, do allow better security since more incorrect choices must be attempted to arrive at the password by such attempts. However, the problem with all such types of password systems, is that the user is expected to memorize his/her password. A four-digit password is work enough to memorize, a longer password is even more difficult. As well, a user may have many such passwords to memorize as required by many different computer programs or computer-based machines he/she normally uses. What typically happens in such cases is that persons write their passwords down on pieces of paper they keep on their desks or in their pockets, and security is badly compromised. Or to avoid needing to write their passwords down, persons may choose easy to remember passwords such as their pet's name or the last four digits of their telephone number, etc. Again, security is again compromised, since this information is usually readily available to others who may want to try this information as a possible password choice for that individual. (Another reason why security is compromised in such cases is because it is often possible to program another computer system to try all the four-digit numbers or all the words in a dictionary, etc, in order to inappropriately enter a password protected system.) As daily life in a technological society involves use or more and more computer-based machinery, and the consequences of using such computer-based machinery becomes more important, the issue of memorizing passwords or using simple words as passwords, becomes more and more serious.